Telegraph system



1. N. CORREIA.

TELEGRAPH SYSTEM.

APPLlCATION FILED AUG. 14, I918.

Patented Jan. 4, 1921 2 SHEETS-SHEET I.

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//1 van /0 Joio Car/42M J. N. CORREIA. TELEGRAPH SYSTEM. I APPLICATION FILED AUG. I4, 1918- 1,364,725. Pate ted Jan. 4,1921.

2 SHEETS-SHEET 2.

//7 van /0/ J0 40 M Cor/e137 y W AW pert cryptogrammatist.

UNITE ST OFFIQE.

301 .0 N. CORBEIA. OF NEW YORK. N. Y.. ASSIGNOR TO VJESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEGRAPH SYSTEM.

Application filed August 14, 1918.

To all whom it may concern:

Be it known that/I, JoZio N. Corinna, a citizen of Portugal, residing at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Telegraph Systems, of which the following is a-full, clear, concise, and exact description.

This invention relates to telegraph systems and more particularly to systems for rendering secret telegraphic service.

The principal object of the invention is the provision of a telegraph system wherein means is provided for expediting the transmission of secret messages.

In attempting to safeguard the contents of telegraphic messages of a confidential nature by seeking to render them intelligible only to an addressee or to certain attendants at telegraphic stations, it has in general been the accepted practice to employ secret codes of the so-called fixed form. In the use of such codes it is well understood that a message is first enciphered and transmitted in a suitable cryptic form, following which it is deciphered or decoded through the application of a proper key mutually understood by the addressor and the addressee. Although many ingenious secret codes devised by expert cryptographers may effectively battle the efforts of moderately proficient decoders, it is nevertheless awell known fact that practically any fixed secret code may be readily analyzed and deciphered by an ex- W'hen due importance is placed on the two fold contingency that irregularities may permit an expert to have access to code messages and that others may surreptitiously obtain the necessary information or key whereby a code may be deciphered, the conclusion is warranted that in general fixed codes may be considered as inadequate to afford the secrecy desired.

' Since fixed codes may be considered as relatively unreliable, an alternate method for safeguarding the secrecypf telegraphic communications may provide for automatically varying a telegraphic code, adding nonessential impulses, and also deleting portions of the signals with respect to each one of a plurality of line conductors, to thereby provide a service oi. such intricate and irregular cryptic form that it may battle the expert cryptogrammatist while no predetermined decoding or key information would be pos- Specification of Letters Patent.

Patented Jan. 4, 1921.

Serial No. 249,822.

sible for the use of persons who may unautl'ioritatively cut in? on or tap a telegraphic circuit.

To the end that the foregoing objects may be attained, the present invention contemplates the employment of electroresponsive devices respectively under the control of telegraphic transmitting and receiving equipments located at remote points on a line circuit, the'arrangement to be such that, in a system of so-called double key transmission, impulses corresponding with dots and dashes may be switched or'interspersed between a plurality of line conductors or the polarities of the transmission currents may be irregularly varied with respect to the dots and dashes during the time they may be en route between such remote points. Although the telegraphic messages may thus be rendered unintelligible to persons whomay tap the hne conductor or conductors, the automatic functioning of the devices of this invention will nevertheless result in a message being properly reproduced through the automatic control of suitably arranged receiving devices.

This invention is illustrated diagrammatically in the accompanying drawing and, for the sake of clearness, only so much of a telegraphic equipment has been shown as will be necessary to a ready and clear understanding of the system.

In Figure 1 of the drawing there is shown equipment at a transmitting and receiving station respectively, between which two line conductors are arranged in a manner suitable for practising the features of this invention. In Fig. 2 of the drawing there is shown an alternate arrangement of the equipment illustrated in the first figure. In Fig. 8 is shown an alternate arrangement in which a single line conductor is employed between a. transmitting and a receiving station.

In describing the operation of this system, attention will first be directed to Fig. 1 of the drawing. The reference character T indicates equipment which may be understood as located at a telegraphic transmitting station from which two line conductors L and L extend to an equipment R which may be located at a receiving station. At the transmitting station there is provided a rotary switching device, comprising sections A, B, C and D, controlled by means of'a magnet 11. The armature of this magnet is provided with a stepping pawl 12 positioned to engage a ratchet wheel 13 which may operate a common shaft, to which may be suitably fixed contactor arms 14, 15, 16 and 17, associated respectively with the four sections of the switch. At the receiving station B there is provided a rotary switching arrangement which differs from the switch at the first station only in that it comprises but two sections A and B. At the transmitting station, the keys 20, 21 and 22 respectively control the operation of relays 23, 24 and 25 in establishing intervals of current by way of the various s vitch sections A, B, C and D with the line conductors L and L The keys 20 and 22 may be understood as respectively controlling the transmission of dot and dash impulses, while the key 21 may be employed in the transmission of impulses over the line conductors L and L in such a' manner that these currents, while serving to render the current effects in the lines unintelligible, will however not produce any effects in the telegraphic receiving device at the distant station R.

A switch 36 at the transmitting station may be positioned to bring the control or stepping magnet 11 of the rotary switch equipment either under the control of the key 20 or the key 22. At the receiving station the line conductor L is routed through the winding of a line relay 40, while the conductor L is connected through the winding of a second line relay 44. At the transmitting station the line conductor L terminates on the blades or traveling contactor members 16 and 17 of the switch sections C and D, while the line conductor L is connected common to the contactor arms 14 and 15 of the switch sections A and B. Each of the several switch sections is respectively provided with ten contactor points or segments and by means of a predetermined arrangement of connections between these segments and six bus conductors 3035, which extend to be controlled by the transmitting relays 23, 24 and 25, the three keys 20, 21 and 22 may at different moments, depending on the position of the rotary switches, become respectively effective in cohtrolling currents over either one of the line conductors L and L or, at predetermined positions of the rotary switches, either one of the keys may respectively render currents effective over both of the line conductors simultaneously. At the receiving station. a source of current 47 may be controlled by the line relays 44 and 40 in such a manner that, through bus conductors 48, 49 and 50, circuits may be completed through predetermined ones of the segments 110 of the switch sections A and B at this station to extend over either a conductor 51 or conductor 52 in respectively controlling two relay type receiving devices 53 and 54. For convenience of description, the latter devices have been represented as sounders whereby a dot reproduced by the device 53 may produce a sound corresponding with dot signals, while the device 54 may produce a differently toned sound which may correspond with dash signals. A switch 56 is employed to connect the stepping magnet 11 of the rotary switch to be controlled either by the relay receiving device 53 or the second relay device 54.

In more specifically describing this-system, a few transmission operations will now be assumed and traced through the various steps necessary in their transmission from the station T to the station B. As a first example, let it be assumed that during a time the equipment may be in the position in which it is shown in the drawing, the dot key 20 may be depressed, and current from a grounded battery 18 may thereupon complete circuit over the switch point 37 and blade 36 to energize the stepping magnet 11. The forward movement of the ar mature of this magnet withdraws the pawl 12 from the tooth of the ratchet wheel 13 in which it is shown, and permits it to engage the neXt forward tooth. No movement of the switch, however, will take place at this time nor so long as the key 20 is held in its closed position as will presently appear. In addition to energizing the stepping magnet 11, closure of the key 20 also operates the relay 23 to establish a battery 19 to energize the bus conductors 30 and 31. The bus conductor 30 being connected common to segments 1, 3, 5 and 6 of the switch section B, while the conductor 31 is connected common to the segments 1, 3 and 6 of the switch section D, it follows that current from the battery 19 flow from these bus conductors outwardly over the contactor arms 15 and 17 respectively to the line conductors L and L thereby operating the line relays 40 and 44 at the receiving station. At the latter point a circuit may now be traced from the battery 47 contacts 46 of the relay 44, contacts 42 of the relay 40, thence by way of the bus conductor 50 which is connected common to the segments 1, 3 and 6 of the distributer sec tion B. Current from this battery may therefore traverse the contactor arm 15, bus conductor 51 and the winding of the receiving relay 53. Operation of the latter relay causes it to emit a sound which may be readable as a dot impulse, while closure of the contacts of this relay connects a bat tery 55 over the switch point 57 and switch blade 56 to energize the stepping magnet 11 of the rotary switch. Energization of this magnet results in advancing the stepping pawl 12 to the next forward tooth in the ratchet wheel 13 in a manner similar to 60 lay receiver 54 to earth. Operation of the that already described for the stepping con trol at the first station.

' Assuming now that the key is released,

the stepping magnet 11 at this station renected from its bus conductors and 31, thereby deenergizing the lines L and L to release the line relays and 44 at the receiving station. Separation of contacts 42 and 46 of these relays disconnects the battery 47 from the circuits already traced, whereupon the receiving device 58 may be released and restored to its normal position. Release of the latter relay disconnects the stepping magnet 11, whereupon retraction of its armature will cause the stepping pawl 12 to advance the contactor arms 14 and 15 to come to rest on their respective segments 2, thereby positioning the stepping switch at the receiving station to correspond with the positions of the contactor arms of the several distributer sections at the transmitting station.

As a second example, let'it now be assumed that the key 22 is depressed for the purpose of sending a dash impulse signal to the distant station. Since the blade 36 of the three-point switch is positioned to bring the operation of the rotary or stepped switch under control of the key 20, closure of the key'22 at this time will be non-effective with the stepping magnet 11. Accordingly the relay 25 will alone respond to the closure of this key. The contacts of relay 25 now establish the battery 19 to energize the bus conductors 34 and 35. Since the bus conductor 34 is connected common to segments 4, 8 and 9 of the switch section D, it will be noneffective at this time since, as already described, the contactor arm 17 now rests on the segment 2. For the bus conductor however, a circuit may be traced to segment 2 of the switch section C.

therefore current from this point may complete circuit over the contactor arm 16 and. line conductor L to energize the line relay 44 at the receiving station. A circuit may now be traced from the battery 47 by way of the contacts 46 and 41 of the relays 44 and 40 respectively, thence by way of the bus conductor 49, segment 2 of the switch section A, contactor arm 14 and conductor 52, thence through the winding of the re latter relay reproduces a soundwhich may be understood to correspond with a dash impulse. Although the contacts of this relay are now closed, they will be non-effective at this time to include the battery with the stepping magnet 11, since the blade 156 of the three-point switch is positioned to the opposite contact 57. On the key 22 being released at the transmitting station, the relay 25 restores to disconnect the battery 19 from the line conductor L thereby permitting the relay 44 to restore and release the signal 54. Since the stepping magnets 11 at each station were not affected through the operation of the key 22, the various arms of the stepped switch at each station continue on their respective segments 2.

As a third example, transmission of an impulse which may serve only for the purpose of complicating the impulse intervals in the line circuits without affecting the receiving devices at the distant station, will now be considered. Accordingly let it be assumed that the key 21 is depressed to operate the relay 24, whereupon the battery 19 will be connected through the contacts of this relay to energize the bus conductors 32 and 33. The bus conductor 32, being connected to segment 2 of the switch section D, current therefrom will flow outwardly over the line L to energizethe line relay 44 at the receiving station and, since the bus conductor is connected common to the segment 2 of the switch section B, current therefrom may flow outwardly over the line conductor L to energize the line relay 40 "at the distant station. Since this position of the line relays 40 and 44 establishes their contacts 42 and 46 respectively to energize the bus conductor 50 from the battery 47, it will be seen that no effects will result on the receiying devices 53 and 54 due to the fact that the bus conductor 50 is connected common to the segments 4, 8 and 9 of the switch section A and tothe segments 1, 3 and 6 of the switch section B at the receiving station. The circuit of the receiving devices 53 and 54 therefore stand open-circuited due to. the fact that the respective contactor arms 14 and 15 of the switch sections at this station are at this time on their respective contacts 2.

From the foregoing description it will be clear that dot and dash impulses originating at the station T, may be similar with respect to their duration or period and that, due to the rotary switch, such impulses may be irregularly varied with respect to the respective stations may be positioned to close their respective contacts 38 and '58, thereby placing the associated stepping magnets 11 under the control of current intervals corresponding with dash impulses.

Referring to Fig. 2 of the drawing, the arrangement shown therein differs from the first arrangement principally in the elimination or" the extraneous impulse control key 21, the absence of intermediate line relays at the receiving station and the elimination of the two switching sections C and D at the transmitting station. In all other respects and in general, the method of operation and the results obtained by means of this alternate arrangement are the same as those already described in connection with the arrangement shown in the first figure of the drawing. In Fig. 2 reversal or transposing switches 26 at each station provide for reversin the control of dot and dash signal intervals, that is, during the time the switches 26 may be thrown to their respective positions 27, the dot key 20 may control the relay 23 for establishing positively poled currents from the associated battery with the cont actor arm 14: of the switch section A and during the time the equipments are positioned, as shown in the drawing, such currents may complete circuit through the contact 1 of the switch sec tion A. to traverse the line conductor L contactor arm 14 of the switch section A at the receiving station, thence by way o1 the bus conductor and the left-hand blade of the switch 26 and the conductor 63 to energize the relay receiving device 53. In a corresponding manner dash impulses originating at the key 22 may energize the relay 25 at a time the equipment is positioned as shown, during which current from a negatively poled battery at the latter relay may then complete circuit over the contactor arm 15 of the switch section B to traverse the line conductor L contactor arm 15 of the switch section B at the receiving station, a bus conductor 61 and the right-hand blade of switch 26 and a conductor 62 to energize the relay device 54: which corresponds with the dash impulses. From this description it will be clear that during a time the switch 26 at each station may be thrown to their opposite positions 28, current impulses originating by manipulation of the key 20 may still become effective with the receiving device 53, while effects resulting from the operation of the key 22 may still become effective with the receiving device 54 at the distant station, transposition of the relation of the keys 20 and 22 with respect to the sounders 58 and. 54 being possible through opposite positioning of the switches 26 at the two stations.

For the control of the stepping magnets 11 at each station, the respective switch blades 36 and 56, as positioned in the drawing, place these magnets respectively under the control of the key 20 and the receiving relay 53 at the respective stations and through the manipulation of the key 20, the release stroke of these stepping magnets causes the respective movement of the contactor arms 14: and 15 in the same manner as that already described in connection with the corresponding equipment in the first figure or" the drawing.

Referring to Fig. 3 of the drawing, the arrangement shown therein differs from those already described in connection with the first and second figures of the drawing principally in the arrangement-of the equipment whereby only a single line conductor is necessary intermediate the transmitting and receiving station. Assuming for the purpose of illustration, that the reversing switches 26 at each station are thrown to their positions 27, operation of the key 20 at the transmitting station will connect a battery 18 to energize the associated stepping magnet 11 and also to establish current by way of the contactor arm 14 and segment 1 of the switch section A to operate a relay 39. The latter relay thereupon establishes an associated source of positive current with the line conductor L, in response to which let it be assumed that a polar relay 65 at the receiving station will be biased to close its contacts 67. This line current also results in the operation of a neutral relay 68 connected in series with the line relay 65. Therefore current from a battery 17 may now be traced through the contacts of the relay 68, the contacts 67 of the relay 65 to segment 1 of the distributor section A, thence by way of the contactor arm 14 and the left-hand blade of the switch 26 to energize the receiving device 53. The latter device, in addition to producing a sound which will be understood as indicating a dot impulse, also establishes the battery 55 to energize the stepping magnet 11. pon the key 20 being released at the receiving station, relay 39 will disconnect positive battery from the line L, there- 7 by permitting the relay 68 at the receiving station to disconnect the battery 47 from the receiver 53. This operation respectively deenergi zes the stepping magnets 11 at each station, whereupon the contactor arms la and 15 will be moved, as already described in connection with the other figures of the drawing, to rest on their respective segments 2.

In transmitting a dash impulse the key 22 may be now closed to establish the battery 18 over the contactor arm 15, segment 2, to energize the relay 39. Although the latter relay connects the positively poled battery over the line conductor through the relay 65', this polar relaycontinues on the same bias as established by the positive 1mpulse previously initiated by operation of the dot key 20. For controlling the receiving device 54, however, the relay 68 now operated completes a circuit which may be traced over the contacts of the relay 68 and the contacts 67 of the relay 65, thence by way of segment 2 and contactor arm 15 of the switch section B and the right-hand blade of the switch 26, through the winding of the receiving relay 54 to produce a sound which will indicate a dash impulse.

Since the switches 36 and 56 at the respective stations are positioned to connect the dot key 20 and the dot receiving relay device 58 to respectively control the associated stepping magnets 11, these magnets are un affected by the described operation of the key 22 and receiving device 54, and accordingly the rotary switches continue in their present positions on their respective segments 2. It now the key 20 is depressed to send a dot impulse, current from the battery 18 will flow through the contactor arm 1a and the segment 2 of the distributer section A to operate the relay 29, whereupon the associated negatively poled battery will be connected over the line to operate the neutral relay 68 and to bias the polar relay to close, its contacts 66. At the receiving station a circuit may now be traced from the battery at? over the contacts of the relay 68, the contacts 66 of the relay 65, thence by way of segment 2 and contactor arm 14 ot' the switch section A and the left-hand blade of the switch 26 to operate the receiving device 53. Since this receiving device will reproduce a dot signal and also connect the battery 55 to operate the stepping magnet 11 at the receiving station, opening of the key 20 at the transmitting station will result in relays 29, 68 and 53 being released, whereupon retraction of the stepping mag net armatureat each station will move the respective contact arms to their associated segments 3. The transposing switches 26 at each station may be employed for service, as already described for the corresponding switches in Fig. 2'of the drawing.

From this description of the arrangement shown in Fig. 3, it will be clear that through the operation of equipment debeen shown and described, it will be understood that in situations where it may be desirable a so-called double pen receiving recorder may be employed in substitution of such sounders. In such an arrangement one pen would be controlled by dot impulses while the other pen would be controlled by dash impulses in the recording of a message.

What is claimed is:

1. In a signaling system, a transmitting and a receiving station, double key means for controlling impulses of uniform duration to represent dots and dashes in signaling between said stations, and rotary switching means controlled in said signaling for varying the relation of said dot and dash impulses with respect to said double key means.

2. In a signaling system, a line conductor connecting two stations, a first and a second key for transmitting impulses to represent dots and dashes respectively, a selector switch at each of said stations, receiving means responsive to the actuation of either of said keys, and means operative upon the depression of one of said keys for advancing the selector switch associated therewith.

In a signaling system, a line conductor connecting two stations, a first and a second key for transmitting impulses to represent dots and dashes respectively, a relay individual to each of said keys, means responsive. to the energization of either of said relays, and receiving means operative due to the operation of saidmeans to give an audible signal to represent-a desired character of a message.

4. In a signaling system, a line conductor connecting two stations, a first and a second key for transmitting impulses to represent dots and dashes'respectively, a selector switch at each of said stations, a pair of relays individual to each of said keys and controlled thereby, receiving means at said second stations, means operated due to the energization of either of said relays for operating said receiving means, and additional means responsive to the operation of said receiving means for advancing said selector switch at said second station.

5. In a signaling system, a line conductor connecting two stations, a plurality of transmitting devices at one of said stations for transmitting signaling impulses to the other of said stations, a receiving device at said latter station responsive to impulses transmitted by each of said transmitting devices, a selector switch at each station, and means responding to the actuation of one of said transmitting devices to advance said selector switches.

6. In a signaling system, a plurality of line conductors connecting two stations, a

phiraiity of transmitting devices at one of said stations for transmitting signaling impulses to the other of said stations, a receiving;- d-evice at said latter station responsive to impulses transmitted by each of said transmitting devices, a selector switch at each station, and means responding to the actuation of one of said transmitting devices to advance said selector switches to thereby Vary the relation between said transmitting means and said line conductors.

In witness whereof, I hereunto subscribe my name this 6th day of August, A. D. 1918.

JOAO N. CORREIA. 

